×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

modal analysis from thermal load

modal analysis from thermal load

modal analysis from thermal load

(OP)
I have a question regarding modal analysis after applying thermal load on the structure.

I have built an aluminum structure model. My reference temperature is the room temperature (70F), which I am mentioning in my MAT1 card.

I need to do the modal analysis at 69F and -20F. This is what I have written on NX Nastran

CEND
TITLE = modal analysis
ECHO = NONE
SUBCASE = 1
SPC = 1
TEMP = 100
SUBCASE = 2
STATSUB = 1
DISPLACEMENT(PLOT) = ALL
ESE(PLOT) = ALL
METHOD = 1
SPC = 1
BEGIN BULK
TEMPD 100 -20.
MAT1 1 1.+7 .33 .101 1.2-5 70.


The modal frequencies will naturally increase when the temperature is cold. But, I am seeing the other way around. My analysis predicts frequencies lower for cold temperature (-20F) than at 69F.

Is there anything I am missing?

Thanks

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources